Idling issues?

[53GMC]

Hey everyone....

my 1996 S10 4x4 vortec V6 needs a diagnosis....

when i first crank the truck up, it runs great (idles around 1000 RPM). If i horse the motor just a little, when i let off the gas it idles back around 1000RPM but will dip up and down from 1000 to around 750.
Any ideas what this could be caused from?
I have already changed the throttle/idle regulator out but it continues....

help?

[68C15]

Originally Posted by 53GMC

I have already changed the throttle/idle regulator out but it continues....

do you mean the Idle Air Control valve?
what you have is at first a high idle and then a hunting idle. both signs of a vacuum leak.
does the cruise control, heater mode selector (floor defrost vent function), 4x4 work correct? chase the hoses using the sticker on the fan shroud as a reference.
you could also have a leak where the plastic upper manifold meets the lower.
without a smoke machine it is gonna be hard to find.
you would need a scan tool to watch the fuel trims in order to do the carb cleaner thing.
if the hoses turn out OK you may consider just going ahead and doing the upper plenum gasket set. it's not too spendy or tough. Fel-Pro MS95816 is about $35-40 list. use ALL the parts included. do not skip the throttle body gasket.

[53GMC]

Thank you 68C15,

I will chase some hoses and see if i cannot find a leak somewhere - hopefully ill be able to.

I was told that the part i replaced was called a throttle regulator sensor....is that different from the idle air control valve? if it is different i will probably try to replace it...